In the battle of humans versus machine on the warehouse floor, some companies have found common ground.

Instead of developing technology to completely replace manpower, these firms are designing robots meant to work alongside people. These robots, for example, can guide workers to items to be picked or can transport goods across a warehouse to be packed and shipped.

Deutsche Post AG
’s DHL is testing “swarming” robots at a facility in Memphis, Tenn. These machines help workers pick out medical devices that need to be shipped quickly. Quiet Logistics Inc., which fulfills online orders for retailers like Bonobos and
Inditex SA
’s Zara, uses the same type of mobile robots in one of its warehouses.

Known as “collaborative” robots, they are small and relatively cheap—costing tens of thousands of dollars—compared with miles of conveyor belts and automation systems that run into the tens of millions. The new robots are designed with the majority of warehouses world-wide in mind, where orders continue to be fulfilled manually by people pushing carts up and down aisles.

Robotics firms pitch them as a way to help people work faster and boost productivity during busy times, such as the holidays, when extra labor is harder to find. Surging online sales and a tight labor market have made it more difficult and expensive to fill warehouse jobs.

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“It’s not meant to replace human labor, but you can get greater throughput with the same size workforce,” said John Santagate, an analyst with IDC Manufacturing Insights, part of research firm IDC.

For example, the robots can slash the number of steps workers take to fulfill an order. But they don’t grab objects off shelves, a task that is simple for humans but tricky to automate, though developers are getting close.

RK Logistics Group, a firm that runs warehouses for high-tech and industrial customers, leased three robots to ferry semiconductor parts when it needed to double its output at a 300,000-square-foot facility in Livermore, Calif.

“I physically could not fit any more people in the building,” said Cindy Traver, the company’s senior director of operations.

Employees pick parts off shelves and place them on blue racks on top of the robots, which then glide over to workers at stations where orders are packed and shipped.

The robots, made by San Jose-based Fetch Robotics Inc., now handle 30% to 50% of the items the facility ships each day, in about half the time it takes a human worker, and without a large, upfront investment, Ms. Traver said. She plans to add five large robots to move heavier parts.

Such robots aren’t yet widespread compared to more-established technologies, like the shelf-moving robots developed in the mid-2000s by Kiva Systems Inc., which
Amazon.com Inc.bought in 2012.

It can take years for technologies to move from the pilot phase to widespread use. Most operators want to see a few success stories before investing in new technology, said
Tom Bonkenburg,
a partner at St. Onge Co., a supply-chain engineering and consulting firm.

Many collaborative robots resemble motorized platforms fitted with shelves and touch screens. They use sensors to navigate past people and forklifts.

Their lower price point could speed adoption, analysts say. Some run between $30,000 and $40,000 per unit, plus software and licensing fees.

This year, 6 River Systems Inc., a Massachusetts company co-founded by former Kiva executives, rolled out “Chuck,” a robot that leads workers through aisles, lighting up when it reaches the next item to pick.

The swarming robots that DHL is testing work in groups. At its Memphis facility, workers assemble multiple orders at once. The swarming robots help manage this complex job by parking themselves next to each item’s location. Workers place the requested item on the robot and go on to the next machine.

“The worker doesn’t have to look for the product, the robot tells them exactly where it is,” said Bruce Welty, chairman and co-founder of Locus Robotics Corp., which makes the robots. Once the order is complete, the robot carries it over to a packing table, then returns to the aisles with another assignment.